Joints of bolted flange are widely used in water mains. It is the only reason why a proper bolt or ASTM A193 Grade B7 tightening system in flanged joints is a necessity. This type of precaution assists in governing the stress variation in the components of flange joint. In case not done perfectly, the possibilities of leakage are greater at pipe joints throughout the operating situations.
There should be a fixed placement of Stainless Steel 304 Bolts by tightening them accurately and that of gaskets as well as their location in a flanged joint which will help confirm a leakage-free joint. Along with the assistance of proper bolt or ASTM A193 Grade B8 tightening, it will even assist you confirm that there is distribution of uniform load in all the Stainless Steel 316 Bolts without damaging the gaskets. Here, you’ll understand how you can tighten the bolts properly of the flange.
Earlier than you start with the real flange bolting, the gasket, bolts/nuts, flange want some type of observation.
Checking flange points earlier than bolt up
In case there is any leakage throughout the flanged joint, the design of gasket material stops the surface of flange from any kind of seals and imperfection them. You can check the limits that a gasket can seal successfully. You should review the surface of flange carefully and confirm there are no dents or gouges. Surface finish of the flange should exist according to the suggestion of the maker for specific gasket materials.
The suggested values of the flange surface irregularity areas follows:
- Jacketed Clad or Metal Gaskets: 63 to 80 rms
- Solid Metal Gaskets: 63 to 80 rms
- Spiral Wound Gaskets: 125 to 250 rms
The sense of rms stands for main square. The roughness specification is generally millionths of an inch as the normal of peaks and valleys measured from the flange surface midline. The suggested radius of the flange is generally 1/16″, and the tool of round-nosed should have 30 to 55 serrations for each inch in a concentric or spiral pattern.
Now here are some important points to confirm before the flange bolts of duplex fasteners manufacturer are installed.
- Confirm proper gasket cleaning areas earlier than insertion. In the case of serration harm, re-roughness is a must.
- In the case of ASTM A182 F11 not meeting the needs, don’t forget the refinement of the piping parts.
- As per to clause, allowed tolerances are as mentioned below:
- The flange faces alignment should be according to the design plane within the measurement of 1 mm in 200 mm across any specific diameter.
- The arrangement of the flange bolts should be within 1/8 inch extreme offset.
- Check the flanges are parallel or co-axial earlier than you insert the gasket in between the pipe.
- Check the gasket confirming it is completely free from all the defects.
- The gasket location should assist to confirm the full sealing.